Multisystemic viral diseases of ruminants Flashcards
(106 cards)
1
Q
Bovine Herpesvirus-1 also known as?
A
Infectious bovine rhinotracheitis (IBR), redness, necrotic rhinitis, pustular vulvovaginitis (IPV), Infectious pustular balanoposthitis
2
Q
Family and genus of bovine herpesvirus-1
A
Family Herpesviridae
Alphaherpesvirus
3
Q
Primary host of IBR/bovine herpesvirus-1
A
BEEF cattle (feedlots, range)
4
Q
Primary host of infectious pustular vulvovaginitis (IPV)
A
Still an infection with bovine herpesvirus-1… just like IBR
Disease of DAIRY cattle
5
Q
Age range of affected cattle for IBR or IPV
A
No age range preference
6
Q
What has caused an increase in incidence of BHV-1?
A
Intensive farming (both beef and dairy)
7
Q
IBR/IPV/BHV-1 has a ______ mortality and _____ morbidity
A
High morbidity, low mortality
8
Q
Do IBR and IPV have the same serotype of BHV-1?
A
Yes, same serotype but can be differentiated genetically
9
Q
Transmission of IBR
A
Transmitted aerosol mostly, but also direct and indirect mucosal contact with infected secretions or abortions
10
Q
Transmission of IPV
A
Sexually… close proximity of animals enhance transmission
11
Q
Clinical signs/lesions of BHV-1
A
Respiratory form (sudden onset of fever accompanied with profuse nasal and ocular discharge) for IBR
Genital form for IPV
Abortion (weeks after infection, last trimester)
Ocular form (conjunctivitis)
Systemic form (seen in calves less than 2 weeks old)
CNS form
12
Q
Respiratory form of BHV-1 (IBR only)
A
Characterized by sudden onset of fever accompanied by profuse nasal and ocular D/C
Nasal discharge starts serious but becomes mucopurulent with crusting around bares… accompanied by coughing, increased RR, increased lung sounds, and open mouth breathing
Severely inflamed nasal terminate and nasal mucosa (red nose) with NECROSIS, ulceration, and plaques (necrotizing rhinitis)
Very high morbidity, low mortality
Predisposes cattle to infection with bacteria(mannheimia) and the resultant viral/bacterial infection is known as SHIPPING FEVER
13
Q
Genital form of BHV-1 (IPV only)
A
Lesions seen on reproductive tract of cows and bulls develop 2-3 days following coitus
In cow, frequent urination, tail switching, slight vaginal discharge… small postures, small white necrotic areas and ulcers seen on Velva and pens
Lesions heal easily.. NO INFERTILITY problems
14
Q
Abortion in BHV-1
A
Occurs weeks after infection… usually in last trimester of pregnancy
It is a SEQUELA of respiratory infection
15
Q
Ocular form (winter pinkeye) of BHV-1
A
conjunctivitis and profuse lacrimation, often in absence of respiratory disease
16
Q
Systemic form of BHV-1
A
Seen in newborn calves less than 2 weeks old
Calves infected in-utero or soon after birth- OCCURS IN CALVES THAT HAVE NO ANTIBODIES TO BHV-1
Acute disease characterized by high fever, anorexia, respiratory distress… MORTALITY IS VERY HIGH
17
Q
CNS form of BHV-1
A
Seen sporadically in cattle
incoordination, rumor, convulsion, HIGH CASE FATALITY
Bovine herpes encephalitis is usually caused by bovine herpesvirus-5, but can be observed with BHV-1
18
Q
What usually causes bovine herpes encephalitis?
A
Bovine herpesvirus-5, but can be seen with bovine herpesvirus-1 as well
19
Q
Which forms of BHV-1 have high case fatality?
A
CNS form and Systemic form
20
Q
Pathogenesis of BHV-1
A
Incubation period is 1 week, causes a LATENT INFECTION
BHV-1 infest moist mucus membranes… mucosal lesions are usually ULCERATIVE, INFLAMMATORY, and NECROTIC!!!
Replication starts locally in mucosal cells, spreads to submucosa, infects sensory nerves and taken up by Macs
Virus migrates up the sensory nerve and becomes LATENT in nuclei of the neurons (ganglia)
Necrosis of mucosa
Infected Macs carry virus to LN–> infect and go latent in T-Lymphocytes… infected lymphocytes can cause placental and fetal infection, resulting in abortions
Viral recrudescence in latent infected neurons and t cells allow virus to re-infect mucosa, replicate, and spread to other animals… or the placenta (if T-cells)
BHV-1 infected lung Macs cannot function properly, so bacteria replicate and cause secondary infections (SHIPPING FEVER)
21
Q
Diagnosis of BHV-1
A
BHV-1 is on DDx in all upper respiratory tract infections, abortions, and vaginitis
Major clin signs- mucosa NECROSIS, inflammation, and ulceration in nasal passages and trachea
Aborted fetuses show focal disseminated necrotizing hepatitis with IN inclusions
If suspected, submit mucosal swabs in transport media (shipped frozen) to confirm by PCR!!!!
Submit fresh fetus or fetal liver if abortion (FA or IHC can be done on fetus liver)
Serology (paired samples, look for seroconversion)
22
Q
Immunity to BHV-1
A
Mucosal immunity is very important to prevent infection
seropositive animals can still be infected… but probably not clinically ill
BHV-1 can recrudesce even in the presence of circulating antibodies
Vaccines given IN more effective at preventing infection than those given IM
Both CMI and humoral immunity are important (CMI for recovery from infection, humoral immunity to prevent re-infection)
23
Q
Control/treatment of BHV-1
A
Symptomatic treatment
Maternal Ab can persist for up to 6 months, so interference with vaccination
VACCINES AVAILABLE (both MLV and inactivated)
- MLV given either IN or parenterally
- vaccinate beef calves 2-3 weeks before weaning, heifers and bulls 2 weeks before breeding, feeder cattle 2 weeks before entering feedlot (annual revaccination)
- MLV contain "temperature sensitive IBR"- these replicate in upper respiratory tract... SAFE for pregnant cows
24
Q
Bovine leukemia virus also known as
A
Bovine lymphosarcoma or Enzootic Bovine Leukosis
25
Family and genus of bovine leukemia virus
Family retroviridae and is a deltaretrovirus
26
Susceptible species to BLV
ONLY CATTLE ARE NATURALLY INFECTED WITH BLV
Sheep are also susceptible to lymphoma when experimentally infected
There is a MARKED gene3tic predisposition to BLV in cattle
27
Source of bovine leukemia virus
Infected cattle- seropositive persistently infected cattle
28
How is BLV often introduced to a herd?
Newly acquired persistently infected cattle
29
Highest incidence of BLV age range
4-8 years old
Few animals under 2 years develop Enzootic bovine leukosis
30
Transmission of BLV
Primarily via blood inoculation
***BLV is in the leukocytes of seropositive cattle**
insect vectors may play a role in transmission
- blood transfusion, dirty needles, vaccination... can transmit disease
- -transmission of leukocytes in blood!!
- dethroning is considered very important in transmission
- **gloves used for rectal exams can transmit virus
- PROLONGED CLOSE PHYSICAL CONTACT BETWEEN ANIMALS is essential for successful transmission- mingling of heifers with adult herd is important because that is when replacement heifers become infected
-nursing can spread virus but not important source of infection
31
Clinical signs of Bovine Leukemia Virus
2 major forms of disease:
- Lymphosarcoma
- Persistent lymphocytosis
Also see sporadic bovine leukosis (LSA seen in cattle under 3 years old... Juvenile LSA in calves 1-6 months, Thymic LSA, and cutaneous LSA in 1-2 year old animals... animals with sporadic bovine leukosis are BLV seronegative)
32
BLV induced Lymphosarcoma or Enzootic Bovine Leukosis signs
- BLV induced LSA is HIGHLY FATAL, systemic malignant neoplasia characterized by development of AGGREGATIONS OF BLV INFECTED NEOPLASTIC LYMPHOCYTES in almost any organ
- **Affected cattle are BOTH SEROPOSITIVE AND PCR POSITIVE
-decreased appetite, decreased milk production, weight loss, and anemia, and enlarged superficial LN
33
Persistent Lymphocytosis caused by BLV
- benign lymphoproliferative condition seen in HEALTHY BLV infected cattle
- these animals show NO OVERT SIGNS, but have a marked increase in circulating lymphocytes
- these animals rarely develop LSA
- ALL BLV infected cattle (whether healthy, LSA or persistent lymphocytosis) will be seropositive and PCR positive for BLV
34
BLV-induced sporadic bovine leukosis
lymphosarcoma in cattle under 3 years
Juvenile LSA in calves 1-6 months
thymic LSA or cutaneous LSA in calves 1-2 years
Animals with sporadic bovine leukosis are BLV SERONEGATIVE
35
Pathogenesis of Bovine Leukemia Virus
Incubation period is 2-4 years (for either LSA or PL)!!!
- BLV infects and transforms B-lymphocytes and integrates in DNA, forming a PROVIRUS
- there is NO VIREMIA and NO BLV IN SECRETIONS
- transmission is via infected lymphocytes
36
Infectivity of BLV
If 100 cattle are infected experimentally, only 30% will become PCR positive and seropositive... of these 30,
-66% will remain asymptomatic healthy carriers (no PL or LSA)
-30% will develop PL (with or without LSA)
3% will develop LSA
37
Diagnosis of BLV
PCR- very sensitive and used for blood or bulk milk
| Serology (ELISA)
38
Control of BLV
Testing and slaughter
39
Bovine Immunodeficiency virus
lentivirus, associated with lymphocytosis
Many animals are seropositive for BIV but no specific condition has been associated with BIV... except suspect immunosuppression
40
Bovine Viral Diarrhea synonyms
Mucosal disease
41
BVDV family and genus
Family Flaviviridae
Genus Pestivirus
42
Variations of BVDV
2 genotype
- BVDV type 1
- BVDV type 2
2 biotypes of BVDV
- Non cytopathic (NCP)
- Cytopathic (CP) biotypes
Many different strains of BVDV exist within both the genotype and biotypes of BVDV- these strains differ in pathogenicity
43
Do BVDV strains cross-react?
All strains of BVDV are antigenically similar and cross-react serologically
44
Transmission of BVDV
Affects cattle worldwide
-prevalence of BVDEV is high in cattle, buffalos
Several disease forms of BVDV
Transmission is by DIRECT CONTACT (mucosal contact with infected urine, feces, excretion) or TRANSPLACENTALLY
45
Major source of infection for BVDV
Persistently infected cattle that secrete virus constantly
- prevalence of PI animals in herds is low (1-2%)
- prevalence of seropositive cattle in a herd with one or more PI animals is 87%
- in a seropositive beef herd with PI animals, about 10% of calves will be PI calves (poor doers, survive only 1 year)
46
What animals are most susceptible to BVDV
Young and unvaccinated cattle are most susceptible... they become fully susceptible to disease after losing maternal Ab by 3-8 months of age
**Wild rums, sheep, and goats and pigs can also be subclinically infected with BVDV
47
Clinical signs of BVDV/forms of disease
Disease forms depend on environment, age of animals, and infection with specific serotype
1) Benign Infection (Bovine virus diarrhea)
2) Parachute highly fatal diarrhea
3) Fatal Mucosal Disease
4) Thrombocytopenia and Hemorrhagic Disease
5) Reproductive Failure
6) Congenital abnormalities
7) Chronic BCD infection and unthrifty PI calves
8) Immunosuppression resulting in respiratory disease with secondary bacterial infection
48
BVDV disease- Benign Infection
Called "bovine virus diarrhea"
- occurs in immunocompetent seronegative calves and young adults
- inapparent infections... if seen, mild fever, leukopenia, diarrhea
- rapid recovery within a few days and development of Neutralizing Ab
- high morbidity and low mortality
49
BVDV disease- Peracute highly fatal diarrhea
Severe form of disease characterized by RESPIRATORY and ENTERIC signs
- usually caused by BVD type II
- respiratory infection, profuse diarrhea, and high fever, oral erosions and mucosal lesions seen
- all ages of animal affected, mortality highest in younger calves
- infection can last several weeks and outbreak progresses slowly
50
BVDV disease -Fatal Mucosal Disease
* **SEEN ONLY IN PI ANIMALS***
- disease of younger animals <2 years
- signs include profuse watery diarrhea, mucopurulent nasal discharge, erosive/ulcerative stomatitis, dehydration, and death
* ***100% case fatality rate*****
51
BVDV disease- Thrombocytopenia and Hemorrhagic disease
-associated with NCP BVDV type II virus
-bloody diarrhea, petechial/ecchymosis on mucosa, epistaxis, prolonged bleeding
-severe thrombocytopenia <25k platelets
Case fatality 25%
52
BVDV disease- Reproductive failure
Conception failure, fetal mummification, abortion, premature birth and stillbirths
53
BVDV disease- congenital abnormalities
Occurs when gvirus infects fetus during period of organogenesis
-cerebella hypoplasia and hydranencephaly is common
-calves unable to stand and walk normally after birth
Can also lead to calf blindness
54
BVDV disease- chronic BVD infection and Unthrifty PI calves
Animals that don't completely recover from infection can develop diarrhea, evacuation, bloat, hoof deformities, erosive stomatitis, and shabby lesions in perineum, scrotum, and interdigital cleft
-calves born PI may be smaller and fail to grow normally... Usually develop fatal pneumonia or fatal mucosal disease (these calves ARE SERONEGATIVE FOR BVDV)
55
BVDV disease- Immunosuppression resulting in respiratory disease with secondary bacterial infection
Seen mostly in feedlots when calves are grouped together and stressed
56
Pathological signs of BVDV
Abnormalities mostly seen in alimentary tract
- shallow erosions in mouth, esophagus, forestomach, abomasum, and cecum
- in mouth, mucosa has cooked appearance with grayish colored epithelium
-histopath- peyer's patches depleted of lymphocytes with little inflammation in ulcer vicinity
57
Pathogenesis of BVDV
- replicates on mucosal surface and tonsils, spreads to LN, infects lymphocytes, and spreads to all lymphoid tissues and organs... necrosis of lymphocyte-associated gut wall tissues and of mucosal epithelium is basis for lesions observed
- pathogenesis depends upon a multitude of interactive factors (age, immune status, stress, secondary infections)
58
BVDV infection of pregnant cattle and fetal infection
Exposure of cattle to virus at estrus may lead to failure of conception... insemination with BVD infected semen can lead to poor conception... However, after the animal has seroconverted, conception is normal and calf is born healthy
-infection during embryonic period leads to decreased conception rate and return to estrus
- infection of fetus during early fetal life leads to death of fetus (mummification/abortion), congenital abnormalities, or persistent infections
- persistent infection of fetuses occurs when the fetus is infected during early fetal life with a NCP strain... fetus recognizes virus as self... born normally but secretes virus constantly
59
PI calves with BVDV
-persistent infection of fetuses occur when fetus is infected during early fetal life with NCP strain
-PI calves will develop mucosal disease when 1)NCP virus mutates to CP virus... or 2)infected with CP virus that is antigenically similar to NCP virus
~mucosal disease can occur within the first 2 years of life
- PI calves will develop normal immune response to other BVDV strains that are antigenically different to the one they ware persistently infected with (even respond to vaccines)
60
Infection of the fetus
Infection of a fetus early (45-125 days) results in death to fetus- mummification or abortion
- infection of a fetus during period 125-175 days of gestation will result in congenital defects
- infection of a fetus after 180 days of gestation results in fully competent immune response by fetus and elimination of the virus--> calf born with Ab to virus and is virus free
61
Diagnosis of BVDV
Leukopenia in acute mucosal disease
EROSIVE LESIONS (not vesicular)
Virus isolations (FA or IPX)
- NCP BVDV does not cause CPE/Inclusions
- whole blood sample is best sample for virus isolation****
- Feces is not a good sample to submit****
Direct virus identification in tissues- FA, IHV, PCR
Serology on paired samples
62
Treatment and control of BVDV
Detection and elimination of PI animals from herd
Vaccinate breeding animals to prevent fetal infection, vaccinate calves at weaning
Prevent introduction of PI animals into a non-infected herd
63
Alcephaline Herpesvirus-1 and Ovine Herpesvirus-2 synonyms
Malignant catarrhal fever
| -2 forms : African form and US/European form
64
Species affected by malignant catarrhal fever
Considered one of the most important diseases of farmed deer
| Also affects cattle
65
Malignant catarrhal fever characteristics
Erosive stomatitis, gastroenteritis, erosions of the upper respiratory tract, conjunctivitis, encephalitis, and lymphadenopathy
Occurs sporadically (1-2 cases per farm)
***low morbidity, HIGH MORTALITY
66
Malignant catarrhal fever family and genus
Family herpesviridae, gens gamma-herpesvirus
alcelaphine herpesvirus-1 infects wildebeest naturally
Ovine herpesvirus-2 infects sheep naturally
67
2 forms of Malignant catarrhal fever
1) African form
- associated with AHV-1 in wildebeest
- disease is endemic in Africa, but also occurs in US (zoos, exotic animal farms)
2) Sheep associated aka US-European form
- caused by OHv-2 of sheep, endemic in US
- OHV-2 is transmitted from sheep to cattle, bison, and deer in the US
- wildebeest and sheep are inapparent carriers of the virus
68
Transmission of MCF (Malignant catarrhal fever)
Transmission from carrier animals to cattle is by DIRECT contact
- wildebeest transmit AHV-1 to cattle and other rums at calving season though direct contact with wildebeest placenta and new-born wildebeest calves
- OHV-2 is transmitted from sheep all year round in the US... not associated with lambing, and young lambs do not transmit OHV-2
- cattle to cattle transmission cannot be accomplished except by blood transfusion
Cattle and deer sometimes survive for a few weeks are thought capable of transmitting the virus during that time period before they die
MCF occurs SPORADICALLY in cattle, deer, and bison in the US... associated with VERY HIGH CASE FATALITY
69
Can cattle transmit MCF to other cattle?
NO
Only way to transmit disease between cattle is via blood, and cattle are not considered contagious between cattle
70
Clinical disease caused by Malignant Catarrhal fever
1) head and eye form (most common)
2) Parachute and alimentary form
3) Mild Form
71
Malignant Catarrhal fever- head and eye form of disease
Most commonly seen
- sudden onset of HIGH fever
- extreme depression, anorexia, photophobia, nasal and ocular discharges, corneal opacity, diarrhea
- lameness is also noted along with enlarged LN
- CORNEAL OPACITY (chronic bilateral stromal keratitis) begins at limbs and progresses centrally, accompanied by blepharospasm and congestion of scleral vessels
Erosions seen on mouth soft palate, tongue, and gums. (Nasal mucosa is red, necrotic, and covered with fibrinopurulent exudates)
CNS signs may appear (head pressing, incoordination)
Death 7-10 days after onset of symptoms
72
Malignant Catarrhal fever- peracute and alimentary tract form of disease
Common in deer
-characterized by high fever, dyspnea, and acute gastroenteritis
Death within 1-3 days
73
Malignant Catarrhal fever- mild form of disease
Transient fever and mild erosions
74
Pathogenesis of Malignant Catarrhal fever
Virus infects lymphocytes, causes a lymphoproliferative and vascular lesions > there is widespread proliferation of lymphocytes and multifocal areas of necrosis around small arteries that undergo fibrinoid necrosis of the muscle wall > the PATHOGNOMONIC LESIONS of MCF is a necrotizing vasculitis and perivascular cuffing (especially in the brain. Lesions may be immune mediated as a result of CTL attacking and killing the vascular endothelial cells
75
What is the PATHOGNOMONIC lesions of Malignant Catarrhal fever?
Necrotizing vascuitis and perivascular cuffing
76
Diagnosis of Malignant Catarrhal Fever
Clinical signs- sporadic disease with low morbidity and high mortality
At necropsy- erosions and hemorrhages throughout the intestine and oral cavity... generalized lymphadenopathy
Submit various organs (brain, LN, mucosa) in formation for histopath--> necrotizing vasculitis is PATHOGNOMONIC
Blood for PCR
Carrier animal detection through ELISA for AB detection
77
Bluetongue virus synonyms
Range stiffness
sore muzzle
mycotic stomatitis
78
Bluetongue Virus family and genus and morphology
Family Reoviridae
Genus orbivirus
Non- enveloped, double capsid, double stranded RNA virus with segmented genome
79
Serotype of Bluetongue Virus
25 serotype, many seen in the US
Serotype share a common internal antigen (group specific Ag) that can be detected by immunodiffusion
External antigens differentiate the various serotypes (type-specific Ag)
reassortment of genes can occur between serotypes
80
Bluetongue Virus distribution
Worldwide distribution in tropical and subtropical countries
BTV serotype 8 just established itself in Northern Europe, and new serotype have spread throughout the Mediterranean basin recently
81
Susceptible species to Bluetongue Virus
Ruminants, both domestic and wild
Significant disease only occurs in sheep and white tail deer (mostly sheep). Cattle generally undergo subclinical infections but serve as a reservoir and amplifying host for BTV
82
What species is of most significance in Bluetongue Virus?
SHEEP
Most economically relevant, and most significant disease
Cattle are subclinically infected with BTV and serve as amplifying host/reservoir hosts
83
What does clinical disease with BTV depend on?
Environment (vector population)
animal species present
Serotype of BTV involved
84
Where in the US is BTV?
High prevalence in south and west US, but low in Northern US
85
When do outbreaks of BTV occur?
Summer and fall, when the insect vector (Culicoides) is active
86
Transmission of BTV?
Natural transmission is via Vulivoides (in US, Vulivoides variipennis). This requires extrinsic incubation period of 8-10 days for viral transmission
Some virus serotypes will cross the placenta in viremic pregnant ewes and cattle
Virus can be transmitted via semen during AI/natural service. However, bulls will excrete the virus in their semen only when they are viremic
87
Clinical signs of BTV in sheep
In sheep, high fever, then nasal discharge and excessive salivation
- reddening of nasal and buccal mucosa followed by excoriation of buccal mucosa
- tongue and gums are very swollen, tongue may turn purple/blue
- diarrhea and lameness often seen
- a wee or two after fever (first sign), may se torticollis (wryneck)
- complete loss of fleece may occur weeks after infection in those animals that recover
- VERY LONG CONVALESCENT PERIOD
88
Fetal infections with BTV
Occur in sheep and cattle, but only with some serotypes (serotype 8 is notable for ability to cross placenta)
-fetal malformation most often associated with BTV is HYDRANCEPHALY OF THE CEREbRAL HEMISPHERES and ARTHROGRYPOSIS
89
Cattle infections with BTV
Most infections in cattle with BTV are inapparent***
-lesions similar to those seen in sheep can be seen (fever, lameness in all 4 limbs due to laminates, edema of lips, erosive lesions in mouth, nasal discharge, and excessive salivation)
- skin of bares may peel
- BTV DOES NOT CAUSE DIARRHEA IN CATTLE
-infection in early pregnancy can lead to calves being born with hydranencephaly and arthrogryposis
90
Pathogenesis of BTV
Infects and replicates in macrophages, dendritic cells, and vascular endothelium
Virus mediated vascular injury leads to thrombosis of the small arteries resulting in infarct
Widespread petechial hemorrhage and necrosis in most organs with extensive edema
BTV released in blood binds to RBC that are long lived, resulting in viremia
91
Pathological lesions of BTV
BTV CAUSES ARTERITIS****
Virus mediated vascular injury results in thrombosis and tissue infarction--> widespread hemorrhage and edema in most tissues
Mucosal lesions (erosions, ulceration, hemorrhages, and edema) are seen in the mouth, esophagus, and forestomach
The lungs in sheep are heavy with frothy fluid in the air passages
Hemorrhagic lesion at the base of the pulmonary artery*** almost pathognomonic
92
Diagnosis of BTV
Virus isolation (virus labile to freezing temperatures, so store blood and samples at 4*C)
Virus ID via RT-PCR
Serology- Ab detected by immunodiffusion, serotype determined by VNT... paired samples (acute and convalescent)
93
Prevention and Control of BTV
MLV vaccine (but notorious for its ability to cross placenta and infect developing fetus)
DO NOT vaccinate ewes during pregnancy... can result in stillbirths and fetal malformation
94
Epizootic Hemorrhagic Disease (EHD) general characteristics
Very similar to Bluetongue virus but it does not affect sheep
Cattle and DEER are susceptible to infection
95
Epizootic hemorrhagic disease susceptible species
Most importantly, deer
Also cattle
NOT SHEEP
96
EHDV family
Family orbivirus
Shared internal antigens with BTV
97
EHDV. Shares internal antigens with BTV?
yes
98
Serotype of EHDV
10 serotypes of EHDV are known
EHDV-1 and EHDV-2 are the 2 most important types in the US
Geographic occurrence of EHD is similar to Bluetongue (south and west US)
99
Transmission of EHDV
culicoides variipennis, seen seasonally in latesummer and fall
100
EHDV is _____ morbidity and ____ mortality in ____ animal
HIGH morbidity, HIGH mortality in white tail deer only
One of the most important diseases of deer in the US
101
EHDV in white tail deer
In WTD, characterized by acute hemorrhagic disease (high mortality)
causes an acute infection and most affected animals are found dead by hunters
102
Clinical signs of EHDV
Acute hemorrhagic disease in WTD, with most affected animals found dead by hunters
Clinical signs resembles Bluetongue (lung edema, widespread hemorrhages
103
EHDV in cattle
seroprevalence shows it is common in cattle but clinical disease is very rare
EHDV can cause lameness and mouth lesions that resemble vesicular diseases
104
Pathogenesis of EHDV
Infects endothelial cells of blood vessels, causing an arteritis
105
Diagnosis of EHDV
Similar as BTV- EHDV antibodies cross react with BTV
PCR
Serology to detect presence of AB (AGID, ELISA)
106
Ibaraki disease
Virus related antigenically to EHDV. Disease similar to EHDV/BTV
